By way of example, it is known to damp the vibration of a turbomachine rotor element by means of a metal split ring mounted with elastic stress in an annular groove of a rotor element, the opening of the groove facing towards the axis of rotation of the rotor. The split ring in the free state without stress presents an outer diameter greater than the diameter of the bottom of the groove, and it is tightened up in order to reduce its radius of curvature so as to enable it to be mounted in the groove and exert pressure on the bottom thereof.
The operation of the turbomachine gives rise to micro-movements and rubbing between the ring and the annular groove in the rotor, thereby dissipating energy and at least partially damping the vibratory phenomena and the instabilities that give rise to the micro-movements and the rubbing of the ring. Nevertheless, the elastic deformation of the ring in the groove is not uniform over its entire circumferential extent, which gives rise to bending that is substantially zero at the ends of the ring and that increases towards the portion of the ring that is diametrically opposite to split. Thus, when the ring is mounted in the annular groove, the lack of bending of its end portions does not enable them to make contact with the bottom of the annular groove since the outer radius of curvature of these end portions remains greater than the radius of curvature of the bottom of the groove, so it is only the ends of the ring that come to bear against the bottom of the groove, which can lead to local wear of the portion of the groove that is in contact with the ends of the ring.
When the turbomachine is in operation, the air or the gas used for combustion and thrust can flow between the stationary parts and the rotary parts and can escape towards the inside of the turbomachine so as to pass between the bottom of the annular groove and the end portions of the ring that are not in contact therewith. Solid particles conveyed by the air or by the gas can thus become lodged between the end portions of the ring and the bottom of the groove.
During rotation of the rotor, the end portions of the ring are pressed against the bottom of the annular groove by centrifugal forces. These forces are not strong enough to destroy the solid particles that have become interposed between the bottom of the groove and the ring, but they press said particles against the bottom of the groove with relatively high pressure, thereby leading to damage to the ring and/or to the rotor, and limiting the lifetime of these parts.